What is the truth about Tyre Ageing?

Information from Michelin Tyres

Q: Why is Michelin sharing this information about tyre ageing?
A: There is a widespread misunderstanding of how tyres age. Remember: The most important date is NOT the tyres’ fabrication date of manufacture (DOT) but the date of fitting to a vehicle.


Q: The tyre does not age significantly if it has not been fitted. Why?
A: While in stock (pre-fitting), a tyre is uninflated, unloaded, and subjected only to the relatively minor temperature fluctuations of storage facility.


Q: If the Date of Manufacture does not matter, what date DOES matter?
A: The date that the tyre is fitted on the vehicle. During operation, the tyre is subjected to high stresses, road impacts and other conditions which do not exist in storage. Therefore, a tyre ages significantly once it has been fitted.


Q: What are some studies that confirm that tyre ageing is irrelevant in storage, and is only relevant after fitting?
A: Three studies have been done in Korea, Germany and Saudi Arabia. The studies in Korea & Germany show no difference in performance between tyres that are newly made versus tyres that are in storage for 3 years. The Saudi Arabia study shows that a tyre used on a vehicle for 1 year has equivalent ageing to a tyre in storage for 10 years.


Q: Tyres age after fitting. What does Michelin advise in terms of tyre care after fitting?
A: After fitting, the tyre requires very special care during its operational life – care that was irrelevant in storage, such as: Pressure maintenance, alignment, damage inspection, tread depth measurement.


Research shows no difference between the performance of recently-produced tyres versus tyres produced 3 years ago.